Log, May 21, 2004

16 people. Something weird happened last night - the weather forecast predicted partly cloudy skies deepening to totally overcast. Usually any forecast this grim means monsoons followed by occasional hurricanes but tonight the skies were briefly cloudy at dusk followed by a three hour period of quite clear and stable air. The humidity and hence the haze was noticeable but this left the entire sky above 15 degrees easily seen.

We started early tonight, getting the 16" up and running while the Sun was up. Shielding the scope from any stray rays by turning the dome to block the Sun, I turned to the 7% illuminated Moon. There was a lot of early turbulence in the atmosphere causing the craters to wiggle substantially. Just below and slightly to the right of the Moon, it was possible to see Venus. Several visitors got their first daytime view of our sister planet with the unaided eye. Jupiter was easy to see early too but none of us actually caught a glimpse of it before the Sun set.

Venus at 8 to 9% illuminated looked very much like the Moon's crescent. The differences were the cause of an extended discussion. The Moon's "horns" do not go all the way to the middle of the globe or beyond. On Venus the "horns" seemed to actually go up past the middle point. There are really two reasons for this. This simplest explanation is that Venus' atmosphere "smears" the sun light beyond the boundaries the daylight terminator. However there is a second reason why the Moon's "horns" are smaller. Venus is far enough from Earth that for all practical purposes we see the half globe nearest us when we look at Venus. This is not the case when we look at the Moon. We see less than the entire half globe. In fact we actually see only out to the Moon's horizon. While we see almost an entire half globe, the squidgen we don't see is enough to hide the tips of the "horns" tips.

Joe brought his large binoculars to try to fine Comet Neat. I have to admit it, I forgot to bring the comet's orbital elements to update the telescope so that we can find it easily. Joe was able to spot it in the constellation Lynx - having moved about 15 degrees NNE from Praesepe (M44) since last week. It formed a roughly equilateral triangle with Alpha Lyncis and 38 Lyncis which acted as fine guide stars. I went into the dome and slewed the telescope to the approximate area and wonder of wonders I hit the comet dead on the very first attempt. It was only a few arc minutes from being centered in the eyepiece. I was very nonchalant about getting the comet so easily but I have to admit it has been quite a while since yours truly used his now rusty star hopping skills to find something so elusive. In any case Comet Neat presented a fine view in the 40MM eyepiece. The core was a pinpoint and the cloud was sharply defined against the sky background. Lots of folks took a look at the comet through both Joe's binoculars and the telescope. One lady asked me to sharpen the focus because it was so fuzzy. I explained that it was actually a very sharp picture of a very fuzzy object. I described Comet Neat as a space traveling fog bank surrounding a large icy snowball which come to think of it, is just about what a comet is. While I was watching the comet, a satellite crossed the field of view, barely missing the core.

We had quite a few bright meteors streak across the sky last night. It is a bit late for them to be Eta Aquarieds, the most recent shower but they might be stragglers. Other possibilities are space junk entering the atmosphere or simply meteors called sporadics which are meteors from the trails of comets which have long left our skies (tens of thousands of years).

I tried the relatively nearby triangle of galaxies NGC3379 (aka M105), NGC3384 and the much dimmer NGC3389. The images could be made out although NGC3389 was very much at the limit of visibility. We couldn't make out much detail because the haze was enough to flatten the contrast. I looked at M44 in the 16". This is always a disappointment in a large telescope because it is simply too large. Many of the "bees" in the beehive (Praesepe) are off the image at anyone time. Binoculars give a better view. I looked at M95 and M96 since we were in the area. Nothing particular to report about them. Toward the end of the evening Joe and I tried to view M104 which Brad Brown had found earlier in his brand new 5" refractor. The Sombrero was disappointing. By the time we got there, the haze had thickened so much that we couldn't make out much detail. Joe saw the dust lane briefly but I didn't even get that much out of the image.

Jupiter had very poor color contrast but was remarkably detailed otherwise. The four moons were easily picked out, the three inner Moons to the right and Callisto way out to the left. Although there wasn't much color detail, I easily picked out whorls in both of the great bands of storms. The Red Spot presented internal detail and I could count at least seven additional bands at low contrast. Joe turned the telescope to Mars and Saturn while I was chatting with some folks. I have to admit I didn't view them so I'll skip any reports about them. People were disappointed that Mars was so small. Of course it was very far away this year - effectively most of the distances of its orbit and Earth's orbit apart.

As the people started home (and the haze deepened) I tried my skill at splitting some double stars. While the haze can blot out bright object details, it has the ability to provide very stable air for moderate brightness doubles. I turned on the "double star" finder feature of the software and tried HIP51690. These stars in Leo is fairly easy to split. Both stars are of similar magnitude (8.8 and 9.7 respectively) and about 5.5" apart. They are listed as yellow stars but in the color eating haze they both were simply white pin pricks. One of the problems of the double star selector is that it shows all double stars. We tried several stars with no luck until it dawned on me that their separation was tiny. They all appeared as single stars or possibly slightly elongated blobs. Once we went back to picking reasonably separated stars, we came upon HIP50305. These are a pair of nearly identically bright (6.6 and 6.8 magnitudes) blue white stars slightly farther north in Leo than HIP51690. They are only 1.5" apart yet they split cleanly.

Haze started to thicken rapidly. As I watched Porrima dimmed out. Porrima is fairly bright (around 2.8 magnitude), the second brightest star in Virgo after Spica. As Spica itself dimmed to what I would have normally called third magnitude, Jupiter to a poor first magnitude and almost everything else to almost nothing, Joe and I decided it was time to call it quits.

-Les Coleman

Leslie Coleman
Leslie Coleman
Entry Date:
May 21, 2004
Published Under:
Leslie Coleman's Log
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